1. Field of the Invention
The present invention relates generally to shift lever locking apparatus and, more particularly, to apparatus for automatically locking an automatic transmission shift lever of a parked vehicle.
2. Description of the Prior Art
Conventional vehicle automatic transmissions can be switched between park, reverse, neutral, drive, second and first operating condition by manipulation of a shift lever. While in the drive condition, the transmission gear ratio is automatically adjusted in response to the speed of the vehicle from stationary to high-speed. Since operation of the shift lever requires very little force, inadvertent shifting thereof sometimes creates a dangerous situation. For example, a child playing alone in a vehicle can easily move the shift lever from park to one of the drive positions. If, in that event, the vehicle is parked on an incline and the hand brake has been released, movement can occur.
A partial solution to the above problem is disclosed in published Japanese Patent Application No. 93044/73. Proposed thereby is a steering locking system in which an ignition key cannot be turned to an off position and removed unless the shift lever is switched to the park position. However, the system employs either a fluid actuator or an electromagnetic actuator responsive to the operation of the ignition key and is extremely complicated and quite costly. Also, although the steering is locked, the shift lever can still be moved from the park position to a drive position and, therefore, this prior system fails to completely eliminate the aforementioned danger.